The present invention relates to an insulation-displacement connection piece having a stripping and retaining slit for one or more electrical wires.
Such a connection piece is made of a conducting material and is intended to be put into a casing made of an insulating material, for example a synthetic material. The casing is, for example, the casing of a terminal block. In this case, the connection piece is connected to another connection piece. The connection piece may also be incorporated into an electrical apparatus or machine and connect an external wire to an internal device.
Patent EP-0,247,360 describes a connection piece of this type. This conducting connection piece comprises a profiled part, having a hollow polygonal cross section, along which is made, longitudinally, a straight stripping and retaining slit for at least one wire.
The connection arrangement described in this European patent, and which comprises the connection piece described above, also provides for the casing housing the connection piece to have an opening which includes a straight slot for retaining the sheath which extends opposite the stripping and core-retaining slit. This slot allows the wire to be more firmly retained when an axial pulling force is exerted on the wire.
In order for the slit profiled part to be sufficiently rigid, it is necessary to have a relatively large thickness of material.
The object of the present invention is to provide a connection piece allowing sufficient retention of the wire without having to provide an additional retention slot. Advantageously, this connection piece will be rigid enough to allow the thickness of material used to be less than that of the connection pieces of the prior art.
For this purpose, the connection piece proposed by the invention is an insulation-displacement connection piece comprising a profiled part having a hollow polygonal cross section, along which is made, longitudinally, a stripping and retaining slit for at least one wire.
According to the invention, the edges of the stripping and retaining slit form the free edges of an inwardly bent-over part of the hollow polygonal section.
In this way, the retention of a connected wire is very substantially improved. It therefore becomes unnecessary to provide an additional retention slot.
Moreover, such a structure is more rigid than those of the prior art. It is therefore possible to use thinner materials while still achieving sufficient rigidity.
In a preferred embodiment, the profiled part carrying the slit has a cross section corresponding to a U, the free ends of which have been obliquely and equally bent over toward each other, through an angle greater than 90xc2x0, so as to make a space between them corresponding to the width of the slit. In this case, the free ends of the U-shaped section are advantageously bent over through an angle of between 120 and 150xc2x0.
The edges of the slit may be gradually thinned toward this slot, as is already known in the case of the connection pieces of the prior art.
For better introduction of the wire and better stripping of the latter, the slit may advantageously have a stripping mouth obtained by cutting, obliquely and symmetrically, the bent-over parts bordering the slit, at one end of the latter.
The invention also relates to a connector for at least one electrical wire, comprising a conducting connection piece with a stripping and retaining slit as well as an insulating casing provided with an oblong opening, which is approximately parallel to the slit and lies facing the latter, and with a housing in which the conducting connection piece is immobilized. According to the invention, this connector comprises a connection piece as described above.
In one embodiment, the casing also has an opening made in the extension of the profiled part of the connection piece and intended for the tip of an external tool to pass through it, said external tool being designed to allow a wire to be introduced into the stripping and retaining slit.